In a wireless charging system, a power transmitting device may wirelessly transmit power to a power receiving device such as a portable electronic device. A portable device may have a receiving coil and rectifier circuitry for receiving wireless alternating-current (AC) power from a coil in the power transmitting device that is overlapped by the receiving coil. The rectifier converts the received AC power into direct-current (DC) power.
It can be challenging to effectively transmit power from a power transmitting device to a power receiving device. If care is not taken, the wireless charging system may not be sufficiently flexible and power may not be effectively transmitted in some circumstances.